We all get excited when we meet someone who shares the same birthday as us. It feels like you just met a kindred spirit. It’s pretty uncommon to randomly run across someone who was born on the same ...

Imagine you’re at a party. There are 23 people in the room, including you. Someone proposes a bet: “I bet at least two people here share the same birthday.” You do the mental math. With 365 days in a ...